Improved facial esthetics can be fully achievable only if facial preferences of the treated group are known. We hypothesized that facial profile perception and preferences could be influenced by orthodontic treatment.
Differences in facial profile preferences between children with and without an orthodontic history were investigated in a sample of 1626 children aged 12 to 19 years (mean age, 14.8 ± 2.2 years) from 24 public schools in Zagreb, Croatia, randomly selected by using a cluster sampling procedure. Eight profile distortions for each sex, morphed by a digital imaging technique, were used for estimation. Analysis of variance (ANOVA), Bonferroni, and 2 independent sample t tests were used to compare the preferences of the groups.
A straight profile was the most favored in both sexes, regardless of previous orthodontic history. A bimaxillary alveolar protrusive profile with thicker lips was preferred among the female profiles, and a bimaxillary retrusive profile with flat lips and a prominent chin was preferred among the male profiles. Orthodontic history and personal facial profile had little effect, and sex had a slightly greater influence on personal facial profile preferences.
It seems that orthodontic therapy has no clinically relevant influence on facial profile preferences. Depending on the patient’s sex, orthodontists should have different criteria for treating borderline patients with bimaxillary dentoalveolar protrusion and mandibular prognathism.
Improvement in facial esthetics is the main objective of orthodontic treatment. From the times of Kingsley, Angle, and Case, much attention has been devoted to facial balance and esthetics. The introduction of cephalometry shifted the attention from esthetics to hard-tissue norms. Subsequent cephalometric analyses, such as those developed by Downs, Steiner, and Ricketts, incorporated soft-tissue profiles norms, but only as secondary and adjunct to hard-tissue norms. Only recently, soft-tissue analysis started to receive adequate attention. Arnett and Bergman pointed to facial esthetics, soft-tissue profile, and smile line as the most important components of cephalometric analysis. Ackerman et al analyzed the esthetics of posed smiles and developed SmileMesh, a computer application for determining the vertical position of incisors during orthodontic treatment. Sarver and Proffit stated that cephalometric findings are no longer the major determinant of treatment goals in modern orthodontics. Increased interest in facial esthetics stimulated studies on differences in facial preferences based on social status, race, sex, age, and education. Kokich et al demonstrated differences in esthetic preferences among laypeople, dentists, and orthodontists, and concluded that aberrations from ideal that are not esthetically pleasant to orthodontists and dentists could be acceptable to laypeople.
In contemporary orthodontics, decisions about extraction are made not only on the basis of calculated amounts of dental crowding and cephalometric norms, but also from soft-tissue analyses. The lips are supported by the maxillary incisors, and alteration of the incisors’ position changes the lip profile. Thus, extraction of premolars and retraction of maxillary incisors by 4 mm results in approximately 4 mm of lower lip retraction and 3 mm of upper lip retraction. There is some evidence that the sizes of the nose and the chin in relation to the lips influence the attractiveness of the facial profile, and that profile preferences are sex-related. A straighter profile with a more prominent chin is favored in men, and more lip protrusion is favored in women. Although much attention has been devoted to soft-tissue profiles, studies on the perception of facial profiles in children are lacking. The purposes of this study were to determine the facial profile preferences among children and adolescents, and whether the perception of facial profile is influenced by orthodontic treatment, sex, or type of personal profile.
Material and methods
Data were collected during an epidemiologic survey between September 2006 and February 2007 in 24 public schools in Zagreb, Croatia. The schools were randomly selected by using a cluster sampling procedure with special attention paid to the location and type of school. A total of 1626 children (white Europeans) aged 12 to 19 years (mean age, 14.8 ± 2.2 years) were asked to rate the profile distortions. The sample included 713 boys (30.4% with orthodontic history) and 913 girls (41.3% with orthodontic history). The Ethical Committee of the School of Dental Medicine at the University of Zagreb approved this study. For assessing facial preferences, 2 sets of color photographs were used, representing 8 male and 8 female profile distortions. The sets were digitally produced, morphed, and standardized by a method described by Türkkahraman and Gökalp ( Figs 1 and 2 ). The profiles were coded from A to H, representing the following skeletal and dentoalveolar features: (A) bimaxillary dentoalveolar retrusion, (B) straight profile, (C) bimaxillary dentoalveolar protrusion, (D) retrognathic mandible, (E) prognathic maxilla and retrognathic mandible, (F) prognathic mandible, (G) retrognathic maxilla and prognathic mandible with increased overbite, and (H) prognathic and posteriorly rotated mandible with anterior open bite.
The subjects were instructed to rank the profiles on a scale from 1 to 8, with 1 the most esthetic and 8 the least esthetic. The images were presented in a pile for each rater to sort. Male and female profiles were rated separately. The images could be considered to represent typical Croatian profiles. Information on each rater’s age, sex, orthodontic history, and personal facial profile was also obtained. Orthodontic history was assessed as a dichotomous variable—with or without a history of orthodontic treatment. The types of presented profiles were determined visually by the investigators and grouped as convex, straight, and concave.
The data were analyzed by using the statistical software (version 9.0, SAS Institute, Cary, NC). The Levene test was used to determine the homogeneity of variances, and the Kolmogorov-Smirnov test was used to assess the normality of distribution. The 2 independent sample t test was used to compare differences in facial profile preferences for subjects with and without orthodontic history and for the sexes. Analysis of variance (ANOVA) was used for comparing profile groups, with the Bonferroni post-hoc test for subjects with equal variances and the Games-Howell test for those without equal variances. A confidence level of 0.05 was considered statistically significant.
Orthognathic facial profile B was the most preferred, and retrognathic profile E, with a prognathic maxilla and a retrognathic mandible, was the least preferred among both male and female distortions. The bimaxillary alveolar protrusive profile with thicker lips was considered esthetically more attractive among the female profiles (sequence: B, C, D, and A), and the bimaxillary retrusive profile with flat lips and a prominent chin among the male profiles was the most attractive (sequence: B, A, C, and D). As shown in Tables I through III , orthodontic history and personal facial profile had little effect on facial profile preferences, but sex had a slightly greater influence. Specific results are presented below.
|Profile||Subjects||Female profiles||Male profiles|
|Mean||SD||Significance ∗||Mean||SD||Significance ∗|
|Orthodontic history||2.25||1.14||0.036 †||2.97||1.23||0.306|
|Orthodontic history||7.23||1.47||0.306||7.09||1.50||0.018 †|
|Profile||Personal profile||Female profiles||Male profiles|
|Convex||2.03||2.26||0.012 ∗ ,†||1.94||1.61|
|Concave||1.36||0.55||(straight & convex)||1.65||1.50||0.083|
|Profile||Personal profile||Female profiles||Male profiles|
|Concave||4.86||2.33||0.863||3.76||2.47||(concave & convex)|
|D||Straight||4.17||1.48||0.009 ∗ ,‡||4.39||1.44|
|Convex||3.49||1.25||(convex & straight)||4.00||1.64|
|Concave||4.43||1.69||(convex & concave)||4.33||1.29||0.251|
|F||Straight||5.08||1.43||0.018 ∗ ,‡||4.87||1.40|
|Convex||5.66||1.53||(convex & straight)||4.95||1.45|
|Concave||4.76||1.67||(convex & concave)||4.88||1.84||0.94|
|Convex||5.33||1.64||5.76||1.43||(concave & straight)|
|Concave||5.03||1.99||0.794||4.73||1.92||(concave & convex)|